From Pinkham Notch take the Tuckerman Ravine Trail for 1.3 miles up to the junction with the Huntington Ravine Trail, which branches off to the right. Follow the Huntington Ravine Trail all the way up into the ravine, ascending the talus slope known as the Fan until you are about level with the bottom of the Pinnacle buttress; at that point start heading left across the talus, crossing a small stream to get to the base of the route. The start is at an obvious weakness which trends left to a prominent ledge.
Pinnacle is an alpine route with many variations. The way that we did it is probably the most direct and fastest, with a slightly more difficult crux than the classic route via the Allis Chimney, but fewer pitches. This variation basically consists of one pitch of good, interesting climbing up to 5.8 and a bunch of 4th and easy 5th class. As with my other route descriptions, I will only provide the one that I've done.
Pitch 1: Follow the obvious weakness to the big ledge (4th class). Move up a slabby, shallow corner to another ledge and to a more vertical, classic right-facing corner (piton). Climb that (5.4-5.5) and belay on the ledge above. 130 feet.
Pitch 2: Climb up a v-groove slightly to your left (easy fifth class), step out right when you can, then walk up 3rd and 4th class terrain up to the base of a prominent right-facing corner (good rock horn for a belay just below the corner). 150 feet.
Pitch 3: Move up the corner (piton) to its top; then face climb up to prominent cracks under an overhang (several pins). Make some 5.8 moves up to just below the big overhanging rock, then move left. Follow easier ground along the ridge, staying just to the left of the crest, until you reach a small but comfortable belay ledge at the base of a short corner. 200 feet, 5.8.
Pitch 4: Climb the short corner and continue along easy ground, keeping near the top of the ridge, until you reach a huge belay ledge, big enough for a bus. 150 feet, 4th and easy 5th class.
Pitch 5: Climb up a short face above the belay ledge (easy 5th class), then more easy stuff to the top. 100 feet.
Note: This is probably the most efficient way to climb if you break the route into pitches. However, if I were to do it again, I would probably simul-climb the first two pitches, climb the crux section as a single pitch up to the end of the 5.8 climbing, and then simul-climb the rest. In this way the whole thing can probably be done in under two hours even by moderate climbers (even with our method we did it in slightly over three, having four people in the group.)
A good selection of sizes, but don't take a huge amount of gear. That said, if the weather turns bad (as it often does up there) and you need to bail, don't count on rappel anchors - you will need to leave gear.
If you have information about this route that doesn't pertain to any of the other sections, please add it here.